Regarding character sets, and whether or not this is "ASCII". Firstly, there is no such thing as "8-bit ASCII", so if it were ASCII it would only ever return integers up to 127. 8-bit ASCII-compatible encodings include the ISO 8859 family of encodings, which map various common characters to the values from 128 to 255. UTF-8 is also designed so that characters representable in 7-bit ASCII are coded the same; byte values higher than 127 in a UTF-8 string represent the beginning of a multi-byte character.

In fact, like most of PHP's string functions, this function isn't doing anything to do with character encoding at all - it is just interpreting a binary byte from a string as an unsigned integer. That is, ord(chr(200)) will always return 200, but what character chr(200) *means* will vary depending on what character encoding it is *interpreted* as part of (e.g. during display).

A technically correct description would be "Returns an integer representation of the first byte of a string, from 0 to 255. For single-byte encodings such as (7-bit) ASCII and the ISO 8859 family, this will correspond to the first character, and will be the position of that character in the encoding's mapping table. For multi-byte encodings, such as UTF-8 or UTF-16, the byte may not represent a complete character."

The link to asciitable.com should also be replaced by one which explains what character encoding it is displaying, as "Extended ASCII" is an ambiguous and misleading name.

I found I wanted to sanitize a string for certain ASCII/ANSI characters, but to leave unicode alone. Since ord() breaks on processing unicode, I drew these two functions up to help with a saniziter which looked at ordinal values. (Finding "pack" and "unpack" was much better than my own powers-of-256 code.)

function unistr_to_ords($str, $encoding = 'UTF-8'){ // Turns a string of unicode characters into an array of ordinal values, // Even if some of those characters are multibyte.$str = mb_convert_encoding($str,"UCS-4BE",$encoding);$ords = array();

Well, i was thinking about a method to hash a string with md5 in a loose way, so md5("HELLO") isn't the same like md5("Hello"), even, i my case, it is about cd-titles i got submitted by users. So i made some function transforming my string to right what i want

Thisone is the "call" function returning the "loose hash".
It will get only the chars of a string, make them to uppercase and then hash with md5.

I wrote the following function to clean illegal characters from input strings.

(Background: I have a php-based news website. People were writing articles in MS Word, then copy-and-pasting the text into the website. Word uses non-standard characters for opening and closing quotes and double-quotes, and for "..." - and this was resulting in articles on the website that failed XHTML validation)